Gas furnace controlling mechanism



Sept. 15, 1936. A D, MaC EAN 2,054,481

GAS FURNACE CONTROLLING MECHANISM Filed Aug. 5, 1930 2 Sheets-Sheet l Al/e); fl/Yaaleazr Sept. 15, 1936. A. D. M cLEAN GAS FURNACE CONTROLLING MECHANISM Filed Aug. s, 1930 TO CLOSE 25 as, {i9 6 3.5 25

2 Sheets-Sheet 2 gwwzntoc 14/47; 3 ifdci e417 Patented Sept. 15, 1936 GAS FURNACE CONTROLLING MECHANISM Allen D. MacLean, Pittsburgh, Pa., assignor to Pittsburgh Equitable Meter Company, Pittsburgh, Pa., a corporation of Pennsylvania Application August 5, 1930, Serial No. 473,279

2 Claims. (01. 137-439) This invention relates to controlling mechanected in a circuit involving several switches nism for gas furnaces. More particularly, the automatically operable in response to changes invention is concerned with the efficient control at various points in the heating system. A and regulation of the flow of gas through a supsimple solenoid motor may be used if desired.

5 ply line to the burners of a gas furnace. Another object of my invention is to provide 5 In installations of this nature the usual praca valve assembly having a single passageway tice is to insert several valves in the supply controlled by several valves designed and arline, which valves comprise a conventional presranged in such manner that neither valve will sure regulating valve, a hand operated stop valve have any tendency to stick, i. e., resist moveand one or more automatic valves operable in ment thereof during operation. In this con- 10 response to temperature or other conditions at nection, it is an object to maintain said valves in various points in the system. Examples of the independent relationship and out of contact with latter (automatic) type of valve are valves conone another in spite of the fact that they have trolled by solenoids or motors arranged in elecvirtually a common seat.

tric circuits through which the flow of current A further important object of the present in'- 15 is regulated by thermostatic switches that make vention resides in the provision of a valve asand break the circuit in response to temperasembly wherein several valves are adapted to ture variations in the heated rooms, within the l se a mm n valve p r one of said valves furnace and adjacent the pilot light, being motor-controlled, and wherein the motor- When a plurality of separate valves is discontrolled valve has no tendency to be Cl sed by 20 posed in the gas supply line in the manner just fl d pressures in t s ydescribed, the pressure drop between the main Other objects of this invention will appear in and the burners becomes undesirably high and the following detailed descripti an appended the final pressure is then too'low for proper and claims when studied in conjunction with the acefficient operation. This is because the total panying drawings i h ch: 25

pressure drop is equal to the sum of the separate Figure l is an elevaiienal e w o edrops caused by frictional resistance in the sev- W at diagrammatically, the y m f s neral individual valves. Accordingly, it is a privention, including a gas furnace and special ma object of the present invention to remedy a v assembly in h gas pply n nd this condition by providing a system wherein a Figure 2 is an enlarged View, a y in Ve ti- 30 single valve port is utilized in th supply line, cal cross section, of the valve assembly seen in which port is opened or closed by one or more Figure valves in response to a plurality of independent With further reference to the drawings, variations in such conditions as pressure, temwherein like characters are pl y to desigperature, etc This valve port may be formed nate like parts, the letter F indicates any 0011- 35 in a single valve body, whereby the total pres- Ventienal y of s fu ce to the burners of sure drop is only that resulting from the re- Which (not seen) gas is d y ay Of a pp sistance caused by a single valve. pipe 3 and manifold inlet tubes 4. Controlling It is an object of this invention to provide, in mechanism. including a valve ly A ina system of the class described above, a valve serted in the P line s p v d fo evern- 40 assembly having a single valve port or passageing the fi of gas to the furnace. way that is opened and closed in response to The Valve assembly A comprises a Comp e pressure variations in the gas supply line, in Valve V, a motor assembly and a P s u e response to various temperature or other regulator The complete Valve Comprises a 515 changes in the heating system, and in response y Casting 5 having r aded inlet and outlet to manual effort. More specifically, it is a major ends 6 and 7 respectively, f r c nnection with object of the present invention to provide, in a the nl pi 3, a partition 8 separating he gas furnace system, a valve assembly in the gas ends 5 and 7, and an upper pp t ng and supply line having a single passageway housing section 9. The partition 8 has a vertical trolled by a pair of independently actuated circular port or opening therein'for establishing 50 valves, one of which is movable in response to Communication between ends 6 and I, whi h variations in gas pressure and the other of which opening terminates at its upper edge in a seat is movable by a motor. The motor may be opshaped, as indicated, to cooperate with the conierable manually as well as by power, and prefercal seating portion I2 of a pressure-regulating ably comprises an electric rotary motor convalve I3. Surrounding this seat the partition 55 carries an annular leather pad l4 that forms a horizontal seat for the relatively sharp free circular edge of a second valve I5 of inverted cup shape.

The valve I5 is designed to be reciprocated vertically in several ways (later described) and is properly guided during such movement by a set of guides I6 formed in the casting 5. The valve I3 is likewise reciprocable, and is guided by free engagement of its fins or spider H with the wall of the port II. The spider I! has a central hub l8 into which is screwed one end of an actuating pin H. The latter is operated by the regulator R in the following manner.

The regulator comprises a pair of complemental casing sections 2| and 22 flanged at their edges and secured together, with a flexible diaphragm 23 gripped therebetween, by bolt and nut assemblies 24. The diaphragm cooperates with the section 2| to form a pressure chamber 25. The section 2| is rigidly secured to the lower side of the valve casting by screws 26, a flexible diaphragm 21 being gripped between the casting and said section to prevent fluid from entering the pressure chamber 25 by way of an opening 28 in the casting. This diaphragm serves a further purpose as will appear later.

A bolt 29 has a clevis-shaped upper end 3| pivotally connected by a pin 32 with the valve actuator I9, and has its body portion threaded and projected downwardly through the diaphragms 21 and 23. The latter has a pair of stabilizing and strengthening pans 33 backed against the ,opposite sides of its central portion and firmly secured thereto by washer assemblies 34, 35 and a pair of nuts 36 screwed on the bolt 29. The washers 34 preferably are made of sheepskin and the washers 35 of tin. A similar set of washers and nuts is utilized to secure diaphragm 21 to, and seal it with respect to the bolt 29.

Regulating pressure fluid is admitted to the chamber 25 from the discharge side of the valve body by way of a tube 31 that is driven through vertically aligned openings in the casting 5 and the section 2|. The joint is rendered leak proof with white lead. The pressure exerted on the diaphragm 23 is resisted by a coil spring 39 that is interposed between said diaphragm and an abutment 4| secured to the upper end of a screw 42 that is threaded through the lower end of the section 22. This screw is provided with a lock nut 43 whereby it may be adjusted and held in any predetermined position to vary the resistance of the coil spring. A closure cap 44 covers the lower end of the screw and section 22.

The regulator just described functions in substantially the same manner as do similar mechanisms of this type. It controls the position of the valve I 3 in response to pressure variations on the furnace side of the valve. The valve l3 has no tendency to stick or resist movement, since it is freely guided, is pivotally connected to the operating bolt 29 and is never in contact with the valve l5 despite the fact that both valves have virtually a common seat adjacent a single valve port. The auxiliary diaphragm 21 is designed to balance the valve l3, i. e., the upward force exerted by inlet pressures on valve I3 is counterbalanced by a downward force exerted by inlet pressure upon said diaphragm. The other valve, I5, is operable by the motor assembly M in the following manner. 4

The motor assembly M comprises a casing 45 that houses an electric motor (not seen) which raises a plunger 46 when current is supplied to the motor and which releases said plunger when the electrical circuit is broken. For a more complete disclosure of this motor mechanism reference may be had to Patent #l,678,202 wherein there is fully shown a motor which, upon receiving current, makes a certain number of turns while simultaneously lifting a valve stem by way of a train of gears and a rack. When the valve reaches fully open position the motor stalls, and holds said valve in such position until the current is cut off, at which time a spring causes the valve to move to closed position.

The plunger 46 projects downwardly through a flexible diaphragm 41 that is secured to the lower side of the housing by a dished plate 48 and machine screws 49. The plunger has an integral collar 5| against which the diaphragm is locked and sealed by a pair of nuts 52 that are screwed on a threaded portion of the plunger. The plate 48 has a central opening 53 to permit vertical movement of the plunger and nuts.

An abutment plate 54 is telescoped on the lower end of plunger 46 and prevented from falling off by a washer 55 held in engagement with the plunger end by a collar 55. The collar is formed integral with a special screw 51 which is screwed into the plunger end axially thereof. A coil spring 58 surrounds the plunger 46 andreacts between the dished plate 48 and the abutment plate 54 with a tendency to thrust the plunger downwardly. The head of the special screw 51 is inserted in a forked and slotted portion 59 of the valve 15, whereby the latter is moved vertically in response to plunger reciprocation and is freely guided during such movement by the set of guide elements IS.

The motor assembly just described is mounted, as illustrated, upon the supporting section 9 of the valve casting 5, and is secured thereto by a threaded locking collar 6|. It will be observed that any gas pressures, tending to seat the valve l5 or maintain it closed, are counterbalanced by the upward pressures against the diaphragm 41. When electrical current is flowing through the motor the plunger 46 is lifted against the resistance of the spring 58 and the valve I5 is then in open unseated position. However, should the electric circuit be broken, the plunger will be released and the valve firmly seated by the coil spring 58. Current normally flows through the motor and is subject to interruption only when such conditions arise in the furnace system that it becomes desirable to close the valve l5. An automatic current control system is provided, as follows (see Figure 1):

Power is taken from a pair of mains 62 and stepped down in a transformer T for use in a valve controlling circuit. This circuit comprises a line 63 leading directly from the transformer to the motor and a line 64 passing from the transformer to the motor by way of several automatic switches S, S1 and S2. The circuit through the motor is completed only when all of these switches are closed.

. The switch S is adapted for disposal in a room heated. by the furnace and includes a thermostatic element 65 which moves downwardly to break the circuit (as indicated) when the room temperature exceeds a predetermined maximum. The valve l5 then closes to shut off thesupply of gas to the burners. When the temperature is below said maximum the element 65 is disposed high enough to maintain an unbroken circuit.

The switch S1 is, in the illustration, in all respects like switch S except for the fact that it is designed to respond to furnace conditions. The furnace condition of a hot water furnace is the temperature of the water heated thereby; of a. hot air furnace it is the temperature of the air being heated; and of a steam boiler it is either the steam temperature, steam pressure or the water level. When the furnace condition arrives at a selected or undesirable predetermined point, (as when the temperature becomes too high, the pressure too high or the water level too low), the switch S1 opens the circuit and permits the valve I5 to close. When furnace conditions are normal the switch is closed.

The third switch, S2, is like the switch S except that it is opened and closed in a reverse manner. That is to say it responds in such manner to temperatures induced by a pilot light that it remains closed when subjected to heat from the pilot light and opens when there is no heat, as when the pilot light is out. The pilot light is the small perpetual flame adjacent the gas burners and it receives its gas from the line 3. Hence should the pilot go out for any reason, it is desirable and necessary that valves l5 be closed toprevent the flow and dangerous accumulation of unburned gas in the furnace. The condition of the pilot light is intended to be embraced in the expression furnace conditions heretofore referred to.

Under certain conditions it may be desirable or necessary to operate the valve l5 manually. For this purpose a manipulating knob is provided at one side of the housing 45, this knob being secured to a shaft 66 that is journaled through the housing and designed to engage the internal mechanism to lift the plunger 48 when the knob is turned counter-clockwise. A small locking plunger 61 is mounted to slide axially in the housing wall and, when the valve I5 is almost fully open, this plunger may be pressed inwardly into the path of the internal mechanism to latch the plunger 46 against return movement by the spring 58.

An arm 68 projects outwardly from one side of the motor housing 45. This arm is oscillatably mounted and internally connected with the plunger 46 in such manner that the outer end of the arm swings up and down simultaneously with the respective closing and opening movements of the valve l5. The swinging end of the arm has a hole 69 therein for connection with a chain or the like (not shown) that may be hooked up with the damper or air supply regulator of the gas furnace. In this manner an automatic regulation of the air supply may be had, with the' damper control positioned to correspond properly with the position of the gas valve I5.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What I claim is:

1. A valve assembly comprising, in combination, a valve body having a single port for establishing a fiow therethrough, a valve seat formed around said port, a shut off valve designed to cooperate with said seat, an electric power unit 'mounted adjacent said valve and connected thereto to operate the same, a balancing element disposed between said valve and said power unit, said element being connected to said valve and having sufficient area exposed to any pressure fluid flowing through said port to counterbalance any fluid pressure tending to close the valve, whereby the latter may easily be operated by said power unit, a second valve designed to cooperate with said single port and arranged to move independently of said shut off valve, a pressure responsive device connected with said second valve to control the latter, and means for counterbalancing the fluid pressures tending to close said second valve.

2. A valve assembly comprising a valve body having a port therethrough, a valve seat formed around said port, a shut off valve designed to cooperate with said seat, an electrical power unit mounted in alignment with said valve and adapted to operate the same, a second valve designed to cooperate with said port, means on said sec ond valve cooperating with said port for guiding the movement thereof, a pressure responsive device connected to said second valve to control the latter, and means for counterbalancing the fluid pressure tending to open said second valve.

ALLEN D. MACLEAN. 

